The total electric flux leaving a spherical surface of radius 1 cm that encloses an electric dipole is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Zero
An electric dipole is a pair of equal and opposite charges \( +q \) and \( -q \). By Gauss’s law, the flux through a closed surface depends only on the total charge enclosed. The flux is the same for a closed surface of any size, so the radius of 1 cm has no effect.
The sphere encloses both charges of the dipole, so the total charge inside it is:
\( \begin{aligned} q_{\mathrm{enc}} &= (+q)+(-q) \\ &= 0 \end{aligned} \)
\( \begin{aligned} \Phi &= \frac{q_{\mathrm{enc}}}{\varepsilon_0} \\ &= 0 \end{aligned} \)
Every field line that leaves the sphere near \( +q \) enters it again near \( -q \). So the outward flux and the inward flux are equal, and the total flux is zero.
NCERT (2026-27):
Electric Dipole – “An electric dipole is a pair of equal and opposite point charges q and –q, separated by a distance 2a.”
Gauss’s Law – “We state Gauss’s law without proof:
Electric flux through a closed surface S \( =q/\varepsilon_0 \qquad (1.31) \)
q = total charge enclosed by S.”